Several types of prior art hot tub and spa covers (hereinafter referred to collectively as "hot tub" covers) are known. One type of prior art hot tub cover is formed of a flexible vinyl material sewn around foam. This type of cover is disadvantageous for several reasons including the following.
The flexible vinyl used on these covers and/or the manner of joining the vinyl sections is not water-tight which results in the accumulation of moisture inside the hot tub cover. This moisture significantly increases the weight of the hot tub cover, causing deformation (e.g., sagging) and making removal from or replacement on a hot tub significantly more difficult. The extra weight also causes additional mechanical stress which may result in mechanical failure such as foam breakage and the tearing of hinges, seams, or handle attachments. Moisture accumulations may also lead to the growth of microorganisms that degrade component quality.
Additional aspects of these hot tub covers include that the environmental conditions in which they are used tend to cause undesirably rapid degradation of the vinyl material and the thread used to sew vinyl sections together.
Other prior art hot tub covers have attempted to improve upon the above described cover or on other predecessors. These attempts include providing multiple layers of material to try to prevent moisture penetration, increasing structural integrity by (1) increasing the thickness of the insulating foam or (2) providing sometimes complicated support structures and utilizing other materials and configurations to improve a particular performance characteristic.
In general, however, prior art hot tub covers are disadvantageous in that they have failed to produce a cover that is strong, durable (i.e., able to withstand mechanical and environmental stress), efficiently made, inexpensive in both materials and manufacture and that does not accumulate moisture.